Variable electrical condenser



1,623,741 Aprll I5 `1927- .Lv vR MQPNALD l VARIABLE ELECTRI CAL CNDENS ER VFiled Nov. 10, 1922 Patented Apr. 5, 1927.

UNITED sTfATEs y 1,623,141 PATENT OFFICE.

LESLIE R. MGDONALD, OF WESTMOUNT, QUEBEC, CANADA.

VARIABLE ELECTRICAL CONDENSER;

Application led November #10, 1922. Serial No. 600,095.

My invention relates to thatv type of condensers in vwhich areas of conductive material are separated by 'a dielectric, and the capacity ot the conductive areas is varied by separating them more or less widely fromr front view of the condenser; Fig. 2 is a vertical sectional view, taken on the, line 22A of F ig. 1, looking to the lett; Fig. 3 is an edgeview, looking to the left on Fig. 1, and partly broken away to show the interior construction; Fig. 4 is a back view, the back plate and locking ring beingremoved; Fig. 5 is a similar view,with the adjuster disk removed;.and Fig. 6 is a similar view with the detlectable conductor removed.V

The parts of the condenser are preferably mounted in a case lof hard' rubber or similar material, centrally through which passesa suitable operating shaft 2, u on the f ree end f whichis mounted a suita le operating knob 3, carrying an index dial 4 a propriately raduated. In the bottom oft ecase is place a thin sheet-like strip 6 ot' conductive material, one end of which is bent down into a groove 7 in the back of the case and is held therein by a pin 8, which is forced into the groove beside it, and which may be utilized to make electrical connection with it. l

.Another groove, 9, in the back, accommo-A dates another pin` 10, which is pushed in beside and holds the ends of a thin sheet 11 serving toapproximately till the s ace between the pins to the same'level as t ie outer face of thesheet 6. But any suitable means vmay be employed J.for leveling this space.

Overthe sheets 6 and 11 is placed a dielectric, which I have shown as being formed ot a disk 12 of mica,d centrally pierced, to ac.

commodate the shaft 2, and provided with a slot 13, through which passes one end of a thin elastic stri or sheet 14 of suitable conductive materia such as sheet copper or the like, this end being also inserted ^in the groove 9 and held therein by the pin 10 which serves as a connector' to it.k The free Iductor, a superimposed dielectric end of the strip 14 normally presses outward and away trom the mica sheet.

Behind the strip 14 is placed a disk 15, preferably ot' hard rubber or other non-con- Aductive material, spaced from the mica sheet by some suitable means, such as a ring 16, so

that it will rotate evenly with the shaft 2, to which it is keyed, as by a pin 17 .passed through theshaft and llying in a slot 18 in the disk. 4 f l This disk 15 is provided with a radially disposed slot 05 sufficiently large to permit the free portion. of the strip 14 to pass outward through it'when the disk is revolved, the limits ot its' rotation being fixed by suit able stops, suoli as a pin 19'011 thev disk and the arms 20, 2l on the case.

A pin 22 through the shaft`2 behind the case, and a coiled spring 23, pressed against the disk 15 by a washer 24 and nut 25 on the shaft 2, preserve the snug assembly of the par A suitable plate 26 closes the back of the case, andinay be held in place by a spring ring 27 expanded in anv annular groove-in the case. This plate is spaced away from the disk 15 so as to provide room for the strip 14 to rise freely. between them.'

With the parts assembled asdescribed,it will be seenthat if the shai't 2 is turned it will carry with it the disk 15; and it' the movement is anti-clockwise the slot in the disk, will move from the tree end toward the fixed end of the strip 14, allowing the .strip 14 to pass outward through the slOt which intheiillustrations is shown as eX- g tending over three. quarters of a circle..

It willl be well understood by those fa# miliar with the art that detailsfo'f construc- .tion may be modified, as by the' use of equivalents' Without departing' from the spirit-of 'my invention as claimed.

Having thus described my invention, what yI claim, and desire to secure by Letters Patent of the United States, isz- 1. In a variable electrical condenser, the combination of a broad, fiat electrical con`l arallel thereto, a second broad,l fiat and iiexi le conductor normally superimposed on the di'- electric, and means. movable relative to the second conductor, engaging against itto hold it in its normal position yand also en gaging between it and the dielectric to progressively release and shit't portions ot the conductor laterally from its normal position.

Q. In a variable electrical condenser, the combination of a broad, flat electrical conductor, a superimposed dielectric parallel thereto, a second broad, flat and flexible condielectric being normally substantiallyr parallel, and means forv progressively moving part of the second conductor into another and parallel plane, and for holding other parts of the conductor in its initi-al plane.

4. In a variable electrical condenser, the combination of a flat metallic sheet forming an electrical conductor, a superimposed, flat sheet constituting a, dielectric, another-and flexible metallic sheet constituting a second electrical conductor, the conductors and dielectric being normallyT substantially parallel, and non-conducting means tor. .pro gressively moving part of the second Yconductor into another and parallel plane, 'and :for holding other parts ot the conductor in its initial plane.r

5. In a variable electrical condenser, thc combination of a flat metallic sheet forming an electrical conductor, a superimposed, flat sheet constituting a dielectric, another and flexible metallic sheet constituting a second electrical conductor, the conductors and di electric being normally substantially par allel, and. means, rotatable parallel to the normal planes of the conductors, for progressively moving part of the second conductorinto another and parallel-plane, and for holding other parts of the conductor in its initialplane. v o

K(i. In a variable electrical condenser, the combination of a flat, metallic sheet forming an electrical conductor, .a flat dielectric superimposed on the sheet, another metallic sheet, normally substantially llat. forming a second electrical conductor, superimposed on the dielectric andfixed at one point relative to the dielectric, unitary meansforholding the second conductor parallel to the dielectric and for optionally, progressively -moving part of the conductor laterally Without lateral displacement ot the remaining part ot' the conductor.

7. In avariable electrical condenser, the combination of a flat, metallic sheet forming an electrical conductor, a flat dielectric superimposed on the sheet, another metallic sheet, normally substantially flat, forming a second electrical conductor, superimposed on the dielectric and having one end xed and one end free, and unitary means, engaging below the tree end and above the intermediate portion ot the second conductor, and movable towards its fixed end, to progressively change the lateral relations ot the second conductor and the dielectric.

8. In a variable electrical condenser, the combination ot' a fixed, metallic sheet constituting an electrical conductor, aV fixed di electric, another and flexible metallic sheet constituting an electrical conductor fixed at one end and free at the other, said conductors and dielectric being normally disposed in substantially parallel planes, and means, embodying a rotatable element provided with a slot through which the last mentioned electrical conductor passes, for optionally moving portions ot the latter conductor laterally toward or away from the former.

l). In a variable electrical conductor, the con'ibination ot' a fixed strip, of conducting material, curved in its own plane, a super nuposed disk-like dielectric, a resilient strip of conducting material, curved in its own plane and normally parallel to the first strip, and being fixed at one end only, and means, embodying a rotatable, slotted disk, through .which the said resilient strip passes, forl causing an optional, lateral movement ot part ot the latter strip.

10. A variable condenser comprising a fixed element,.an adjustable element, a rotor having a slottherein through which the adjustable element may pass, means for resiliently pressing the rotor toward the fixed element, and means to rotate the rotor.

11. A variable condenser comprising, a support, a fixed element thereon, a flexible movable element adapted to be laid down and picked up from the fixed element, a movable member adapted to move between said elements to operate said movable clev ment, and means for preventing said movable member from contacting upon said fixed element.

12. A variable condenser comprising a pair of elements, and a slotted member through which one ot the pair of elements is adapted to progressively be assed to cause the relative displacement o said elements'.

- LESLIE R. MCDONALD. 

